Field of the Invention
The present invention relates to an electric rotating machine and more particularly to a structure for cooling an electric rotating machine.
Description of the Related Art
To date, as a structure for cooling an electric rotating machine, for example, Japanese Patent Application Laid-Open No. 2012-100477 (Patent Document 1) has disclosed a cooling structure, for an electric rotating machine, that is provided with a rotor having a rotor iron core and a supporting member and cools the rotor; the rotor iron core is situated at the outer circumference side of a rotation axle and in which permanent magnets are mounted, and the supporting member couples and supports the rotor iron core and the rotation axle. An oil flow path for supplying cooling oil to the center axis of the rotation axle is provided in the electric rotating machine; the supporting member is provided with an outer cylinder unit fixed to the inner circumferential surface of the rotor iron core and a disk-shaped supporting body that partitions the outer cylinder into two portions in the axis direction of the rotation axle. There is provided an oil supply means for supplying oil to the inner circumferential surface of one of the two portions of the outer cylinder unit that is partitioned into two portions by the supporting body; through-holes that penetrate the supporting body are provided in the mounting portion, for the outer cylinder unit, of the supporting body.
In the structure disclosed in Patent Document 1, the oil supply means jets (supplies) cooling oil, which has passed through the oil flow path provided along the center axis of the rotation axle, to the inner circumferential surface of the outer cylinder unit so that the permanent magnets embodied in the rotor iron core are cooled.
[Patent Document 1] Japanese Patent Application Laid-Open No. 2012-100477
In the foregoing cooling structure for an electric rotating machine, cooling oil is jetted (supplied) by centrifugal force onto the inner circumferential surface of the outer cylinder unit; therefore, there has been a problem that in some cases, the cooling oil cannot be jetted onto a target place and hence the cooling efficiency of the electric rotating machine is lowered. In particular, as the rotation speed of the rotor becomes higher, airflow in the electric rotating machine is intensified; thus, the foregoing phenomenon becomes more conspicuous.